Fluid pump



Sept. 13, 1960 w. H. CLANCY FLUID PUMP 2 Sheets-Sheet 1 Filed May 15,1958 w. H. CLANCY Sept. 13, 1960 FLUID PUMP 2 Sheets-Sheet 2 Filed May15, 1958 FLUID PUNIP William H. Clan'cy, New Hope, Pa., assignor to Rohm& Haas Company, Philadelphia, Pa., a corporation of Delaware Filed May15, 1958, Ser. No. 735,566

Claims. (Cl. 103-44) This invention relates to apparatus particularlyadapted to the pumping of fluids, more particularly, to pumps of thetype in which the supply fluid is wholly isolated from any part of thepumping mechanism as by the requirements along the flow passage ofpacking glands, and the like.

It has heretofore been proposed in pumps of the expansion or squeezetype to utilize single lengths of tubing extending through a flow-sealedchamber, the pressure of which is alternately increased and decreased toproduce a pumping action. Such pumps have limited output per strokeunless there be a relatively large movement of the walls of the squeezetube. When there is a large movement, such tubing is subjected to stressand strain of large magnitude tending to decrease its life.

In accordance with the present invention, a flexiblewalled tubularmember having a plurality of turns is spirally disposed within a closedchamber filled with a fluid medium. By periodically increasing anddecreasing the pressure applied to the fluid medium, the volume of thetube is alternately increased and decreased for forced displacement ofsupply fluid therethrough. In a preferred form of the invention theclosed chamber is filled with an incompressible liquid. The tubularmember is expansible and contractable. It has a length materiallygreater than the maximum dimension of the closed chamber and iscircuitously disposed therein. Check valves are associated with theinlet and outlet of the tubular member for unidirectional flow of thesupply liquid therethrough. A plunger is reciprocated into and out ofthe incompressible liquid through fluid-tight packing glands. As theplunger moves inwardly it decreases the volume of the closed chamberand, as a result of the rise of pressure on the incompressible liquid,causes the volume of the tubular member to decrease as by change in thecross-sectional area thereof. The extent of change in shape of the tubeneed not be very great with a plurality of turns thereof in order todisplace substantial quantities of supply liquid therein during eachreciprocation of the plunger. Since the plunger changes the pressure onthe tubing by way of the incompressible liquid, there is a directrelationship between the movement of the plunger and the amount ofliquid displaced or pumped per stroke. Thus the device lends itself tometering applications where precision in flow is important.

By making the tubular member thin-walled and of substantial diameter itlends itself to the pumping of slurries and other semi-viscous materialswhich offer considerable difliculty with controlled volume pumps ofconventional design. 7

Apparatus embodying the invention is quite versatile in that atubularmember may be readily cleaned or a second tubular member substitutedwhen it is desired to change from one fluid to another without thepossibility of mixture of any residual part of one with the other.

nited States A atent ice Embodiments of my invention are disclosed inthe accompanying drawings, wherein:

Fig. l is a sectional view of one form of apparatus within the scopethereof;

Fig. 2 is a transverse section taken in the direction of the arrows online 2-2 of Fig. 1;

Fig. 3 is a plan view of a second embodiment with the top removed; and

Fig. 4 is a transverse section taken in the direction of the arrows online 4--4 of Fig. 3 with the top in place.

In the embodiment shown in Figs. 1 and 2, 10 is a cylinder provided withend walls 11 and 12 held in fluidtight engagement with the ends of thecylinder by tie rods 13 to form a chamber 16. The end wall 11 isprovided with an outlet 14 and plug 15 therefor, such outlet permittingfluid to be introduced into the chamber 16. End wall 11 is also providedwith an inlet which through valve 17 is adaptedto be connected to amake-up reservoir (not shown).

End wall 12 contains an aperture 18 located centrally thereof throughwhich passes a piston 19. The piston is held in fluid-tight engagementwith the walls of the aperture, a packing gland 20 being provided forthis purpose.

A second cylinder 21 provided with a plurality of apertures 22 islocated within chamber 16, the ends thereof fitting, respectively, intogrooves in end Walls 11 and 12. Around this second cylinder there isplaced a spirally wrapped tubing 23.

The inlet end of the tubing 23 is connected to a metal pipe 24 whichextends through the wall of the outer cylinder 10, being welded to thewall thereof. The inlet end of the tube 23 is secured to the metal tube24 by any suitable means providing a fluid-tight connection as, forexample, by a hose clamp 25. The outlet end of the tube 23 is similarlyfastened by a hose clamp 26 to a metal tube 27 extending through andwelded to the wall of the outer cylinder 10.

Since the closed chamber is formed by a removable end wall 11, accessmay be had to the hoseclamps 25 and 26 for tightening and loosening themso that the coil 23 may be replaced when desired. It is to be furthernoted that the assembly as shown in Figs. 1 and 2 may, as a whole, bereplaced by another assembly to function with the plunger or piston 19driven by suitable reciprocation means, preferably with adjustablestroke provisions. One form of such a mechanism is shown in UnitedStates Patent No. 2,587,395 to Sheen.

The metal tube ends 24 and 27, to which the ends of tubing 23 areclamped, are provided, respectively, with check valves 30 and 31, sothat fluid flow through the tubing is permitted in the direction shownby the arrows in Figs. 1 and 2 but is prevented from flowing in thereverse direction.

Tubing 23 is of flexible material. For example, it may be of natural orsynthetic rubber, of thin-walled stainless metal, or of any of thesynthetic materials from which flexible-walled tubing can be formed.Depending upon the character of fluid with which the tubing will comeinto contact in normal operation, the kind of flexible material of whichit is formed will be so chosen to be inert to the fluid being pumped andbe such as will withstand undue deterioration in operation.

In themodification shown in Figs. 3 and 4, 40 designates a chamberhaving bottom wall 41, circular end wall 42, and top wall 44. The bottomwall 41 has a spiral flange 45 extending into chamber 40 and in contactwith one side of said flange there is placed a spirally disposed tube46. The ends of tube 46 extend through apertures in the bottom wall 41and end wall 42, respectively, in

fluid-tight relation with said apertures. Each end of tube 46 isprovided with a check valve, respectively designated 47 and 48, topermit flow of fluid in the direction indicated by the arrows.

End wall 42 is apertured to provide a passage 49 for piston 50. Thepiston is reciprocated by any suitable source of power, as is wellunderstood in the art.

The top wall 44 is provided with outlet 51 havingremovable plug 52 topermit fluid to be introduced into the system and with outlet 53 adaptedto be connected with a make-up reservoir (not shown).

In each of the embodiments described above, as is evident, there is aclosed system in which the tubing is surrounded by fluid, either gaseousor liquid.

For controlled volume pumping, i.e., for a known or linear relationshipbetween extent of movement of the plunger 19 of Fig. 1 and the flow offluid being pumped through the outlet passage, the rigid-walled chamber16 will be fully filled with an incompressible liquid such, for example,as water or oil. If the latter, then, for example, of the type used inhydrauic brake systems. When the pumping coil 23 is of the expansibleand contractable type, then as the piston is withdrawn from the chamberthe partial vacuum resulting distends the cross section of the tubing,drawing fluid within the tubing through the inlet check valve in thedirection indicated by the arrows, while at the same time holding theoutlet check valve closed, thus filling the distended tubing with fluidto be pumped. When the piston is moved in the reverse direction theresulting pressure applied to the tubing reduces its internal cubicalvolume, thus forcing fluid within the tubing through the outlet checkvalve while at the same time maintaining the inlet check valve in closedposition.

In a preferred form of the invention, when liquid is being pumped, itpreferably has a liquid pressure-head adequate to assure the completefilling of the tube and without the need for the development of partialvacuum each time the plunger 19 is moved outwardly of the chamber 16.Accordingly, since the pumping coil 23 is at all times fully filled withliquid the volume of liquid displaced therefrom is always a known andpredetermined function of change in volume of the chamber 16 as producedby movement of the plunger 19. The pump lends itself to high pressureand low pressure forced flow of liquids and is likewise applicable tohigh volume, low pressure displacement of liquids, fluids, slurries andsemi-viscous mixtures.

As will be understood by those skilled in the art, instead of a singlecoil a plurality of spirally wound tubes may be employed, each having aninlet and outlet check valve. In this adaptation several diflierentfluids, each through a separate tubing, may be pumped by means of thesingle composite fluid-activating assembly. Alternatively, a pluralityof spirally wound tubings may be connected in parallel to commonheaders, one, for instance, at the inlet ends of the tubings and theother at the outlet ends thereof, the inlet and outlet check valvesbeing provided in the respective headers. Several spirally wound tubingsconnected in series may also be used with check valves at the endsthereof as well as at intermediate points therebetween. When theexpression tubing or tubular member is used herein, it is to beunderstood that it may be of any plane geometric cross section. Suchvariations and modifications, as come within the scope of the appendedclaims, are considered a part of this invention.

What I claim is:

1. Pumping means comprising a closed chamber filled with a fluid medium,an expansible and contractable tubular member having a plurality ofturns spirally disposed within said chamber and having extremitiesextending through the walls of said chamber in fluid-tight engagementtherewith, inlet and outlet valves operatively engaged with saidextremities, respectively, means whereby periodically increased anddecreased pressure may be applied to the fluid medium within said closedchamber to alternately contract and expand said spirally disposedtubular member throughout the entire length thereof within said chamber,and stationary means within said chamber and in contact with said tubingfor holding the latter in its spirally disposed condition.

2. A pump of the controlled volume type comprising a rigid-walledchamber wholly filled with an incompressible liquid, flexible-walledtubing having a length materially greater than the maximum dimension ofthe chamber and circuitously disposed therein, means including an inletvalve connected to one end of said tubing for flow of supply liquid intoone end of said tubing through an inlet passage isolated from saidincompressible liquid, means including an outlet valve connected to theother end of said tubing for flow of said supply liquid from the otherend of said tubing through an outlet passage isolated from saidincompressible liquid, and displ-aceable means movable into said chamberfor decreasing the volume of said chamber for applying uniformlythroughout the length and circumference of said tubing immersed withinsaid incompressible liquid the increased pressure due to said movementof said displaceable means to decrease the net volume occupied by saidflexible-walled tubing and to force liquid therein outwardly thereofthrough said outlet passage.

3. A pump of the controlled volume type comprising rigid walls forming aclosed chamber filled with an incompressible liquid, a multiple-turncoil of flexiblewalled tubing disposed within said closed chamber withthe respective ends thereof in flow communication with inlet and outletpassages extending outwardly of said chamber, a plunger, said closedchamber having an opening for entry of said plunger into said chamber,packing means surrounding said plunger and forming a fluid-tight sealtherewith, inlet and outlet check valves in said inlet and outletpassages for unidirectional flow of supply liquid through said coil, andmeans for reciprocating said plunger alternately to increase and todecrease the volume of said chamber to increase and to decrease thepressure applied uniformly throughout the length and circumference ofsaid flexible-walled tubing by said incompressible liquid first todecrease the volume thereof for forced flow of the supply liquid from,said inlet passage outwardly through said outlet passage and then toincrease said volume to permit flow of additional supply liquid to saidcoil.

4. The pump of claim 3 in which said coil extends upwardly from theinlet end thereof thereby to avoid gas entrapment in any turn thereof.

5. The pump of claim 3 in which additional coils of flexible-walledtubing are disposed within said closed chamber for forced flow of aplurality of streams upon each reciprocation of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS1,899,364 Tennant Feb. 28, 1933 2,377,170 Morgan May 29, 1945 2,377,251Le Clair May 29, 1945 2,403,572 Wittenberg July 9, 1946 2,478,568 CoeAug. 9, 1949 FOREIGN PATENTS 894,503 Germany July 8, 1949

